[regularfry]

This would also affect Exim's pipe filter if it accepted '()' in author names.

[baudehlo]

That depends on whether Exim validates MAIL FROM according to RFC 5321 or not. I would like to assume it does. Rudimentary testing on cam.ac.uk (where Exim was developed) shows that it does, so Exim is not vulnerable as far as I can tell.